a. Field of the Invention
This invention relates to methods for recovering certain vinyl sulfonate monomers.
B. Description of the Prior Art
It is well known to copolymerize various mono-olefinic monomers with acrylonitrile in making polymers from which textile filaments are spun. In the conventional process, unreacted monomers are recovered by a distillation process. Unfortunately, such a recovery process is not effective for unreacted monomers of the type ##EQU3## where R.sub.1 is --H or --CH.sub.3 and R.sub.2 is --CH.sub.2 -- or ##EQU4## in which R.sub.3 and R.sub.4 are -H or -CH.sub.3 and X is H, Na or K for the reason that these monomers are not sufficiently volatile.
Monomers of this type are not usually used as components of textile polymers except in small proportions. Because of the difficulty of recovering the unreacted portion of such monomers and the small amounts of such monomers used, the past practice has been to discard the stream containing these unreacted monomers. The disadvantage of this practice is that these monomers are expensive and only partially biodegradable.
It is known to use carbon for the adsorption of various substances. However, it is not believed that it is known to adsorb the sulfonate monomers of this invention on carbon and then desorb these monomers from the carbon by using acrylonitrile.